Power tools can be used to perform many tasks that were previously performed with hand tools. For instance, some power tools may be used to cut, grind, or polish materials including metal, wood, and stone. These types of power tools often include a motor configured to rotate a tool shaft. The tool shaft may be the output shaft of the motor; alternatively, a transmission may rotatably couple the tool shaft to the output shaft of the motor. The tool shaft of some power tools is terminated with a clamping device for connecting an approximately disk-shaped tool to the tool shaft. When clamped to the tool shaft, the disk-shaped tool rotates with the tool shaft. Depending on the type of disk-shaped tool, a user may cut, grind, or polish a workpiece by contacting the workpiece with the rotating disk-shaped tool.
The clamping device of some power tools requires at least one auxiliary hand tool to connect the disk-shaped tool to the tool shaft. Specifically, clamping devices often include a fastening member, such as a bolt, which is threadingly engaged to a free end of the tool shaft. A first auxiliary tool, usually a wrench, is used to tighten the bolt. When the bolt is tightened a compressive force is exerted upon the disk-shaped tool to couple the tool to the tool shaft for rotation with the tool shaft. The rotational force applied to the bolt, however, is often transmitted to the tool shaft causing the tool shaft to rotate, thereby limiting the torque that may applied to the bolt. Accordingly, many power tools include a shaft-lock lever, which selectively prevents the tool shaft from rotating and permits the bolt to be tightened to a desired torque. Instead of a shaft-lock lever some power tools require a second auxiliary tool, such as a second wrench, to hold the tool shaft in a stationary position as the bolt is tightened with the first wrench. A disk-shaped tool is removed from the tool shaft by securing the rotational position of the tool shaft with either the shaft-lock lever or the second wrench and then loosening the bolt with the first wrench.
The above-described clamping device works sufficiently well for coupling a disk-shaped tool to a tool shaft of a power tool, however, further advancements are possible. For instance, some users may misplace or lose the auxiliary tools required to operate the clamping device. Additionally, some users may use the auxiliary tools to over-tighten or under-tighten the bolt, resulting in the power tool operating with less efficiency. Therefore, what is needed is a clamping device capable of clamping a disk-shaped tool to a tool shaft of a power tool without the need for auxiliary hand tools. What is also needed is a clamping device, which consistently applies a desired level of compressive force to a disk-shaped tool coupled to the tool shaft of a power tool. For these reasons and others, further advancements in the area of clamping devices for power tools are desirable.